Electrical connectors



1954 E. c. CROWTHER 3,152,855

ELECTRICAL CONNECTORS Original Filed April 8, 1960 veb- 28c H 28A 306 Zo I I ma INVENTOR. EdmondCCmwZ/zer 24 e Y best set forth hereinafter.

United. States Patent 3,152,355 ELEtITRICAL CONNEQTORS Edmond C. Crowther, Alden Park Manor,

, Phiiadelphia 44, Pa.

Griginal application Apr. 8, 1950, filer. No. 21,045, new Patent No. 3,072,879, dated Jan. 8, 1963. Divided and this application .iuly 16, 1262, Ser. No. 212,183

3 Claims. (Ci. 339-246) This application is a division of my co-pending application, Serial No. 21,045, filed on the 8th day of April 1960, now Patent No. 3,072,879, issued January 8, 1963.

This invention relates to an electrical connector for removably securing the end of a conductor to a workpiece. More specifically, it relatesto those types of connectors which are adapted to -be' utilized either with what are known in the trade as terminal blocks or as an adjunct to bus bars.

It is an object of this invention to provide an improved electrical connector, which will releasably retain the bare end of a conductor without physically distorting or damaging same.

- Another object of this invention is to provide an electrical connector having excellent conductive qualities but which is simple in conformation and ideally adapted for mass productiontechniques;

Further objects will become more apparent when the specification is read on the accompanying drawing, where- FIG. 1 is an elevation in partial section of an embodiment of the present invention;

3,152,855 Patented Oct. 13, 1964 tion, since the provision of the downwardly extending free end 114 on spring 28h permits and assures aggressive contact of two wires on opposite sides of the connector, where the specific wires have difiering diameters.

FIGURE 3 is a modification of the embodiment set forth in FIGS. 1 and 2 in that it utilizes a single side wall 380 and is adapted specifically for single conductor connections. The other elements, such as screw 26c, spring 280, and base 30c are substantially the same.

FIGURE 4 is another embodiment to the present invention wherein similar parts are designated by similar numetals with the addition of the suffix d. The base 30d of the cage has upstanding wall portions 38d and 40d, as were present in the other embodiments, and in addition, has an intermediately placed flange 118, extending in the samedirection as the walls 38d and 411d, to assist in the centering of the connectors, between the screw shank 26d and either adjacent side wall. in this embodiment is dilferent from the previously described embodiments in that the last bottom helix 120 presents a flat bottom in opposition to the base 30d whereby planar contact is presented instead of the curved or rounded line contact of the other embodiments. The side walls 38d and 40d are provided with grooves 121 and 122, respectively, which assist the connector in retaining the conductors in secured position by preventing the conductors from riding up the upstanding walls in the instances where a single conductor is inserted and the spring 28d should, perchance, become tilted. The final embodiment of the invention is seen in FIG.

5 wherein similar numerals are utilized to designate sim- FIG. 2 is a partial sectional view taken along line 2-2 V invention can be best seen in FIGS. 1 and 2. In this embodirnent the cage 245 includes a base 30b, having a threaded aperture 36!), centrally located therein, and a pair of upstanding side walls 38b and 40b, respectively, along opposite edges of the base 39b. In the present in- I stance, the cage 24b is an integral part of a lateral extension to a bus bar 1118 (as best seen in FIG. 2). The screw 26b has an unthreaded shank portion 110, positioned adjacent its head. Intermediate the unthreaded shank portion and threaded shank portion is a laterally extending shoulder means 112. Spring member 28b, in

,the present embodiment, is a coiled wire spring having a reduced diameter in the last helix which rotatably engages the unthreaded portion of the shank 110and is restrained from axial movement relative to the screw by means of ,the shoulder 112. The free end 114 of the spring opposite to the portion secured on the shank at 110, is adapted to extend downwardly towards the base 30b, for purposes In the present embodiment as seen in FIG. 2, the coiled spring is not necessarily cylindrical in conformation, but father may assume a shape complementary to the shape of the base 30b, in the present instance a square. By utilizing a square spring, rotation is prevented between the spring and the side Walls 38b and 40b, respectively, whereby the surface of the Wires or conductors 76b and 116; will not be'scored by rotary particularly where a wire is to be inserted and removed many times during a lifetime of use. It will be noted that the conductors 76b and 116 are of differing diameters,

motion of the spring. This can be of great importance,

ilar parts, with the addition of the suffix e. In this embodiment a cage of the type shown in the previous embodiment of FIG. 4 is utilized and the variation is presented in the combination of the screw shank and spring loaded portions. In this instance, the screw 26e has an unthreaded shank portion e, which is of considerable axial extent. Axially movable along the unthreaded shank 110e is a washer-like member 123. The washer 123 is non-rotatable relative to the cage 242, but rotatable relative to the screw 262. It can be associated with .screw 26c by known methods, wherein the central aperture of the washer 123 is greater than the unthreaded shank portion lltte, but less than the major diameter of the threaded portion, whereby washer 123 serves as a lower abutment for the coil spring member 28a This device has the distinct advantage in that there is a uniform plate-like member, which presents a planar surface to the conductor 76c. The grooves 121e and 122a serve to prevent the conductor from sliding up the side walls, should the washer member 123 become canted and also permit the use of the connector with larger diameter conductors by accommodating the same in said grooves.

It is believed that the present invention has set forth in its various embodiments a simple and eflicient connector, capable of being produced by mass production methods and resulting in a simple, economical fastener, adaptable to a multiplicity of uses. 7

I am certain that other embodiments of this invention will be apparent to those skilled in the art and it is my intention that I be limited only by the appended claims.

I claim:

1. A helical connector for removably securing the end of a conductor to a workpiece, including a'sheet metal cage having a base and at least one side wall, said base having a threaded aperture, a threaded screw member having a head at one end of its shank and the other end of said shank being adapted to be rotatably accepted within said threaded aperture, helical spring means encircling said shank between said head and said cage and having one end of said spring rotatablyassociated with said The spring member 28d,

shank adjacent the head whereby axial movement of the screw relative to said cage results in an axial movement of said spring relative to said base, said spring at the end remote from the head having at least one convolut the e w th a lea es h n he lead of th heli es in the other convolutions to provide a clamping surface to impinge upon conductor-s which are inserted between said clamping surfaces and the base of the cage, said spring at the end remote from the head also having at least one convolution thereof Wound in a substantially noncircular configuration complementary to said base and adapted to engage said side wall to prevent relative rotation between the spring and said cage.

2, A device of the type claimed in claim 1 wherein at least one of said side walls is bowed outwardly intermediate its upper and lower extremities to accommodate the lateral surfaces of large diameter conductors disposed between said side wall and said screw and against the base.

3. A helical connector for removably securing the end of a onduct t a orkpiec includi g a sh t m tal cage having a base and a plurality of side walls, said base having a threaded aperture, a screw threaded member having a head at one end of its shank and the other end of said shank being adapted to be rotatably accepted within said threaded aperture, said plurality of side walls forming passageways between said side walls and the shank of said screw, helical spring means encircling said shank between said head and said cage and having one end of said spring rotatably associated with said shank adjacent the head whereby axial movement of the screw relative to said cage results in an axial movement of said spring relative to said base, said spring at the end remote from the head having at least one convolution thereof with a lead less than the lead of the helices in the other convolutions to provide a clamping surface to impinge upon conductors which are inserted between said clamping surface and the base of the cage, said helically disposed spring being laterally outwardly spaced from said shank except at its point of connection adjacent said head a distance greater than the lateral extent of said head whereby said cage is adapted to accept a plurality of conductors of varying diameters and said spring means is adapted to cant to resiliently engage all conductors in the connector including those of varying diametral size.

References Cited by the Examiner nnrrnn STATES PATENTS 1,758,978 5/30 Rosen 339246 1,825,130 9/31 Schneider 339254X 1,997,821 4/35 Gzupkaytie -1 l5138 2,712,123 6/55 Wibell et al. 339--246 3,001,173 9/61 Swengel 339-266X 3,068,445 12/62 Crowther 339246 FOREIGN PATENTS 172,565 9/62 Austria.

753,145 4/52 Germany.

880,013 6/53 Germany.

221.093 8/42 Switzerland.

JOSEPH D. SEERS, Primary Examiner. 

1. A HELICAL CONNECTOR FOR REMOVABLY SECURING THE END OF A CONDUCTOR TO A WORKPIECE, INCLUDING A SHEET METAL CAGE HAVING A BASE AND AT LEAST ONE SIDE WALL, SAID BASE HAVING A THREADED APERTURE, A THREADED SCREW MEMBER HAVING A HEAD AT ONE END OF ITS SHANK AND THE OTHER END OF SAID SHANK BEING ADAPTED TO BE ROTATABLY ACCEPTED WITHIN SAID THREADED APERTURE, HELICAL SPRING MEANS ENCIRCLING SAID SHANK BETWEEN SAID HEAD AND SAID CAGE AND HAVING ONE END OF SAID SPRING ROTATABLY ASSOCIATED WITH SAID SHANK ADJACENT THE HEAD WHEREBY AXIAL MOVEMENT OF THE SCREW RELATIVE TO SAID CAGE RESULTS IN AN AXIAL MOVEMENT OF SAID SPRING RELATIVE TO SAID BASE, SAID SPRING AT THE END REMOTE FROM THE HEAD HAVING AT LEAST ONE CONVOLUTION THEREOF WITH A LEAD LESS THAN THE LEAD OF THE HELICES IN THE OTHER CONVOLUTIONS TO PROVIDE A CLAMPING SURFACE 